1/2 inch = 12.7mm Black Solid Clear Faceted Crystal Gem Retainer Ear Plugs 1 Pair Solid Clear Cubic Zirconia Crystal Nickle Free Surgical Steel Grade 316L Size 1/2" (inch) or 12.7mm (milimeters) Stainless Steel (Anodized Black Color) 1 Black Rubber O-ring at the back